Radio and TV stations should reject misleading 'third-party' political ads or insist on changes.

The fact-checking of political ads is a cottage industry in any election year, but the 2012 presidential race has been especially rich in misrepresentations, cheap shots and outright lies. Media critics and services such as FactCheck.org have been working overtime to deconstruct attack ads and quantify their deceptiveness. (The Washington Post bestows up to four "Pinocchios" on deceptive ads, with one Pinocchio indicating "some shading of the facts" and four reflecting "whoppers.")

Now one monitor of misleading ads is trying to persuade television stations that air political ads to engage in their own fact-checking. FlackCheck.org, a project of the Annenberg Public Policy Center at the University of Pennsylvania, is reminding radio and television stations that they are free to reject — or insist on changes in — "third-party" political ads such as those aired by "super PACs."

That might come as news to some broadcasters, which are more familiar with ads placed by the candidates themselves. Under federal law, broadcasters may not refuse or censor candidate-produced advertising even if it is inaccurate or defamatory. But there is no such obstacle to policing third-party ads.

Admittedly, there are gradations of misrepresentation. And with political advertising, as with other kinds, hyperbole is inevitable. Who's to say whether a particular breakfast cereal is the "world's greatest" — or a particular candidate "Wall Street's best friend"? Some assertions in campaign ads aren't easily verified.

But other statements contain factual assertions that can be easily debunked if they are wrong. For example, FactCheck.org has disputed an ad by a candidate for the U.S. Senate in Michigan claiming that President Obama's stimulus "lost 2.6 million more jobs." In fact, the figure was 428,000 jobs. Other misleading ads rely on insinuation. Take "Facts," an anti-Rick Santorum ad produced by Restore Our Future, a pro-Mitt Romney super PAC. Showing an image of a prisoner in an orange jumpsuit, the ad claims that Santorum "even voted to let convicted felons vote." The irresistible implication is that Santorum enabled prisoners to vote while they were incarcerated. In fact, they wouldn't regain the privilege until they had served their time. Rather charitably, PolitiFact Florida, a project of the Tampa Bay Times and the Miami Herald, rated the ad "half-true." Half-true should not have been good enough for a responsible station to air it.

A station that won't approve fraudulent advertisements for products should be at least as vigilant about misleading political advertisements. And in most cases the work will already have been done for them by organizations such as FactCheck.org. Super PACs and other political groups would be more responsible in framing their messages if they knew they had to pass a truth test to get them on the air.